Types of Metal Detecting Activities, page 33:
GOLD NUGGET HUNTING
Gold Metal Detecting Tips
(CONTINUED from previous page)
Identifying Gold
Prior to finding their first nugget, beginners usually experience problems when trying to identify gold.
When visually inspected, gold can be easily confused with similar looking minerals such as pyrite, chalcopyrite, pyrrhotite (magnetic pyrite), pentlandite and gold colored mica.
The yellowish bronze color is the only thing these minerals have in common with gold. But if one knows the properties of gold, each of these minerals can be set aside.
Here are simple ways to distinguish gold from the minerals mentioned above:
1) Gold is the only mineral that can be easily scratched, leaving a residue of gold-yellow powder.
2) While the gold-like minerals are brittle, gold is malleable and will break and flake when struck with a hammer.
3) When fine gold is dropped in water, it will sink rapidly and refuse to move while the minerals will sink slowly and spin around freely.
Once gold is found and held, identifying it next time will not be difficult. Exceptional cases occur when the gold pieces are in extremely fine or microcrystalline form, and a microscope is required to identify them.
Tips for Gold Nugget Hunting
Like in most types of metal detecting activities, research is a key to success in gold nugget hunting. There are four factors to consider when looking for an area suitable for nugget hunting: 1) whether the area is gold-bearing or not, 2) the level of iron mineral content present in the ground, 3) sizes of gold pieces known to be present at the location, and 4) amount of trash. If you plan to detect on mining claims or private property, never forget about getting permission first. And be aware of any possible restrictions for metal detecting on public lands.
The searched ground can be of two types: homogenous and heterogeneous. Homogeneous ground requires minimal adjustment of manual Ground Balance of your detector. Heterogeneous soil contains a variety of iron minerals plus "hot rocks" (highly mineralized stones) and makes the Ground Balance constantly go off. In this case, you will have to continually adjust your metal detector's manual Ground Balance. Detectors with Automatic Ground Balance controls have an incontestable advantage over detectors with Manual Ground Balance.
When you begin gold nugget hunting, first start looking for black sand pockets. Utilize a large search coil and make sure that your detector is fine ground balanced in its All Metal mode. Follow a stream bed that is either wet or dry while holding the search coil in front of you (you do not have to swing it). When the threshold suddenly goes "null" (dies out completely), this will be an indication that you may have found black sand which accompanies gold nuggets.
When you find a gold nugget, think of it as an indicator of more nuggets to be found in the area because a nugget would rarely appear by itself. And if you do not find more nuggets soon, it could be that they are either a) smaller than the nuggets your detector can "see" or b) buried deeper than the detecting depth of your detector.
For the "a" situation, the remedy would be utilizing either a metal detector that operates on higher frequency, therefore is more sensitive to small nuggets, or a smaller search coil which is also more sensitive to small targets and can turn a gold detector of moderate frequency into a high-frequency unit. For the problem in "b" case, the right solution would be utilizing a larger coil to increase the detecting depth.
The perfect solution for both cases would be utilizing two different gold metal detectors - one operating on high frequency and another one being a lower frequency model, or having a nugget hunting buddy who uses a different metal detector. Then the two detectors would not interfere with each other, and the most effective search of the area would be accomplished.